Introduction

The body morphology of Pterotrachea hippocampus is elongate; similar to that in P. coronata but not as streamlined (see the P. coronata page). Instead, the proboscis is shorter and thicker, the visceral nucleus is shorter and tear-drop shaped, and the tail is shorter and less well developed. The eye shape is unique in the genus, with a narrowly- to broadly-triangular shape. The trunk cutis anterior to the swimming fin is thickened ventrolaterally (forming a bib) and the tail terminates in two small, leaf-like lobes, as in P. coronata. Like the other species of Pterotrachea, a swimming fin sucker is present only in males. The geographical distribution is cosmopolitan in tropical to subtropical waters.

Brief Diagnosis

A species in the genus Pterotrachea with the following characteristics:

• Body elongate, comparable in form with P. coronata
  
• Proboscis similar to that in P. coronata, but shorter and thicker
• Trunk cutis anterior to swimming fin thickened as ventro-lateral folds, forming a bib
• Visceral nucleus tear-drop shaped, like that in P. scutata
• Eye shape, in dorsal view, narrowly to broadly trianguler